fix(fs): stop depending on the optional FileSystem#getScheme() (#19470)

* fix(fs): stop depending on the optional FileSystem#getScheme()

FileSystem#getScheme() is optional in Hadoop: the base implementation throws
UnsupportedOperationException, and proxy implementations such as Presto's
PrestoS3FileSystem do not override it. Hudi called it unguarded on filesystems it
did not implement, so opening a log file on such a filesystem failed with
"Not implemented by the PrestoS3FileSystem FileSystem implementation" instead of
reading anything (HUDI-4602).

Adds HadoopFSUtils#getScheme(FileSystem), which returns fs.getScheme() and falls
back to fs.getUri().getScheme() when it is unimplemented. getUri() is abstract, so
every implementation supplies it, and its scheme is what getScheme() returns
wherever both are present. This is the same conclusion as #793, which stopped
HoodieWrapperFileSystem calling getScheme() on the filesystem it wraps.

Routes the seven unguarded call sites through it: isGCSFileSystem and
isCHDFileSystem (the reported read path), registerFileSystem,
HoodieWrapperFileSystem#convertToHoodiePath, HoodieRetryWrapperFileSystem#getScheme,
WriteMarkersFactory's HDFS gate, and HoodieHadoopStorage#getScheme, which is what
the seven HoodieStorage#getScheme callers reach.

isGCSFileSystem's comparison is also flipped to put the constant first, matching
isCHDFileSystem, so a filesystem whose URI carries no scheme returns false rather
than throwing NullPointerException.

* test(fs): say which branch of the helper each assertion covers

Review nit: the assertion messages did not make clear what had gone wrong. Each
now names the filesystem and the branch of the helper it pins - LocalFileSystem
overriding getScheme() so the helper returns what it reports, FilterFileSystem not
overriding it so the helper falls back to getUri().getScheme().

* fix(fs): fail loudly on an unresolvable scheme, and cover the sites this reroutes

Review feedback, all of it well founded.

The fallback no longer returns null. InLineFileSystem is the counter-example in this
module: getScheme() is "inlinefs" while getUri() is URI.create("inlinefs"), which has no
colon and so no scheme, so the two are not interchangeable and the javadoc claim that
they agree was simply wrong. A null surfaced far from the cause as "does not support
scheme null" or "Unsupported scheme :null" with the UnsupportedOperationException
discarded; it now throws with that exception chained. HoodieException rather than
HoodieIOException, since the latter only accepts an IOException cause.

HoodieHadoopStorage memoizes the scheme. On a filesystem without getScheme() the
fallback costs a thrown-and-caught exception, and this is called once per log block via
StorageSchemes.isWriteTransactional and three times per immutable-file write via
needCreateTempFile. A lazy field keeps all five constructors untouched.

Test coverage for what this actually reroutes, none of which any test reached:

- registerFileSystem, HoodieWrapperFileSystem#convertToHoodiePath (the write path) and
  HoodieHadoopStorage#getScheme, via a LocalFileSystem subclass whose getScheme() throws,
  registered as fs.file.impl so it is reached through FileSystem.get.
- isGCSFileSystem and isCHDFileSystem, which become reachable for proxy filesystems for
  the first time here and select different stream wrappers: a scheme-less filesystem
  reporting gs:// now yields SchemeAwareFSDataInputStream and ofs:// yields
  BoundedFsDataInputStream.
- the new unresolvable-scheme failure.

TestFSUtilsWithRetryWrapperEnable#testGetSchema has been inert since HUDI-5286 added it:
it asserted on HoodieWrapperFileSystem#getScheme, which is uri.getScheme() and never
dispatches into the retry wrapper, and FakeRemoteFileSystem overrode getScheme() to
delegate to a real LocalFileSystem so it could not throw. Dropping that override gives
the fake the PrestoS3FileSystem shape and the assertion now targets the retry wrapper,
so it guards both HUDI-5286 and this change. Verified: it fails with the pre-PR helper.

Also drops the try/catch in convertToHoodiePath that only rethrew HoodieIOException
unchanged, dead since ef70de2bba7b, and the duplicated fixture and redundant nested
close in TestHadoopFSUtils.